Shape-Transformable Switch Apparatus Based on Magnetorheological Elastomer

ABSTRACT

In an embodiment a shape-transformable switch apparatus includes an electromagnet arranged inside a housing, wherein the electromagnet has an outer circumferential surface wound with a solenoid coil and is configured to provide a magnetic field when a power is applied to the solenoid coil, a Magnetorheological Elastomer (MRE) disposed on an upper portion of the electromagnet, wherein the MRE is configured to change from an initial soft state to a relatively hard state when the power is applied to the solenoid coil and configured to be pressed and to move upward when the electromagnet moves upward and a switch cover disposed on an upper portion of the housing, the switch cover configured to form a switch shape and to protrude outward when the MRE moves in an upward direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application No.10-2022-0015656, filed Feb. 7, 2022, the entire contents of which areincorporated herein for all purposes by this reference.

TECHNICAL FIELD

The present invention relates to a shape-transformable switch apparatusbased on a Magnetorheological Elastomer (MRE). More particularly, thepresent invention relates to a shape-transformable switch apparatusbased on an MRE, the apparatus using an Electro-permanent Magnet (EPM)that has characteristics in which an N-S polarity is changed by a powerapplied to a solenoid coil, thereby providing a feeling of using aphysical button of a switch by using the MRE that is pushed upward to anoutside resulting from the EPM which is moved upward when a magneticfield is formed on the EPM.

BACKGROUND

Generally, as information and communication terminals such as a notebookcomputer, a smartphone, a tablet PC, and the like, or electronic devicessuch as a video game console, remote control, and the like have beendeveloped, researches have been recently actively carried out to providemore various user experiences (UX) to the users using these informationand communication terminals and electronic devices.

For example, a conventional user terminal shows a two-dimensional planescreen and provides only a simple level of audiovisual feedback forgiving sounds in line with content shown on a screen. However, a recentuser terminal can provide a screen having a three-dimensional cubiceffect and can also provide more complex visual feedback, hapticfeedback, and the like that enable the user to feel a force, a sense ofmovement, a texture, and the like together with a content of theprovided screen.

Here, such haptic refers to a tactile sensation that can be perceived bya user when the user touches an object, and includes a tactile feedbackperceived by a skin touched on a surface of an object and includes akinesthetic force feedback perceived when a motion of a joint and amuscle is disturbed.

Recently, as research on an electroactive polymer has been conducted toprovide a haptic effect, expectations for the use of the electroactivepolymer in various fields such as chemistry, machinery, electricity,medicine, materials, and food are increasing.

For example, the electroactive polymer can be used not only in fieldssuch as a next-generation micro-robot, a micro-aerial vehicle, and soon, but also in industrial fields such as an artificial muscle actuatorand so on.

As such, in an actuator using the electroactive polymer, the actuatorprovides the haptic effect by using a phenomenon in which a polymericdielectric expands and is compressed when a high voltage is applied toflexible electrodes that are disposed at an upper surface and a lowersurface of the polymeric dielectric.

However, in the actuator using the electroactive polymer, since anexcessively high voltage is applied to provide a sufficient hapticeffect, the actuator has a user safety problem and also has a problemthat a physical damage may easily occur.

SUMMARY

Embodiments provide a shape-transformable switch apparatus based on aMagnetorheological Elastomer (MRE), the apparatus using an electromagnetthat forms a magnetic field by a power applied to a solenoid coil, andthe apparatus using the MRE having characteristics in which the MREmaintains an initial soft state when the magnetic field is not appliedbut the MRE is changed to a relatively hard state when the magneticfield is applied. By using the electromagnet and the MRE, when themagnetic field is formed, the electromagnet is moved along a movementguide, and the MRE that is changed to the hard state is moved upward, sothat a switch having the shape that protrudes is formed. Therefore, theapparatus is capable of providing a kinesthetic sensation of a hardfeeling according to an operation of the switch according to whether ornot the magnetic field is applied.

Embodiments provide a shape-transformable switch apparatus based on aMagnetorheological Elastomer (MRE), the apparatus including: anelectromagnet provided inside a housing, the electromagnet having anouter circumferential surface wound with a solenoid coil, and theelectromagnet being configured to form a magnetic field by a powerapplied to the solenoid coil; the MRE disposed on an upper portion ofthe electromagnet, the MRE being configured such that the MRE is changedfrom an initial soft state to a relatively hard state as the power isapplied to the solenoid coil, and the MRE being configured to be pressedand moved upward as the electromagnet is moved upward; and a switchcover disposed on an upper portion of the housing, the switch coverbeing configured to form a switch shape and to protrude outward as theMRE is moved upward.

In addition, the shape-transformable switch apparatus based on the MREaccording to an embodiment of the present invention may further includea movement guide connected to the electromagnet from inside the housing,the movement guide being configured to guide a movement path of theelectromagnet that is moved upward in a magnetic field directionoptionally by the magnetic field.

Here, the movement guide may be provided as a pair of movement guidesdisposed to be upright from inside the housing, and the pair of movementguides may be respectively coupled to guide members that arerespectively provided at opposite end portions of the electromagnet,thereby guiding the movement path of the electromagnet.

In addition, the shape-transformable switch apparatus based on the MREaccording to an embodiment of the present invention may further includea power supply portion configured to supply the power for forming themagnetic field to the solenoid coil that is wound on the electromagnet.

In addition, the electromagnet may be formed of an Electro-permanentMagnet (EPM) in which an N-S polarity is changed by the power applied tothe solenoid coil.

In addition, the MRE may be inserted into and coupled to a mounting holethat is formed in a center of the upper portion of the housing, and mayoptionally protrude from the mounting hole as the MRE is pressed by theelectromagnet when the MRE is changed to the relatively hard state bythe electromagnet.

The switch cover may be formed of a material having elasticity, and maybe configured such that a shape of the switch cover is changed as theMRE protrudes outward through the mounting hole.

Meanwhile, the shape-transformable switch apparatus based on the MREaccording to an embodiment of the present invention may further includea sensing member disposed inside the switch cover, the sensing memberbeing configured to sense a contact state by using a change incapacitance that is changed according to an approach distance of anobject.

Here, the sensing member may be formed of a carbon electrode layer, andmay be attached to an inner side of the switch cover.

In addition, the electromagnet may be configured such that the power isapplied on the electromagnet optionally by the sensing member as thechange in capacitance increases, thereby allowing the MRE to be moved ina magnetic direction.

In addition, the electromagnet may be configured such that the powerapplied on the electromagnet is turned off as a pressure is applied tothe MRE while the switch cover is in a protruding state, therebyallowing the MRE to be moved downward along the movement guide.

Here, the MRE may be changed to an initial state as the power applied onthe electromagnet is turned off, thereby allowing the switch shape ofthe switch cover that protrudes outward to be returned to an initialshape.

Embodiments provide an electromagnet that forms the magnetic field bythe power applied to the solenoid coil, and uses the MRE havingcharacteristics in which the MRE maintains the initial soft state whenthe magnetic field is not applied but the MRE is changed to therelatively hard state when the magnetic field is applied. By using theelectromagnet and the MRE, when the magnetic field is formed, theelectromagnet is moved along the movement guide, and the MRE that ischanged to the hard state is moved upward, so that the switch having theshape that protrudes is formed. Therefore, there is an effect that thekinesthetic sensation of the hard feeling according to the operation ofthe switch may be provided according to whether or not the magneticfield is applied.

In addition, embodiments provide, when the user’s finger approaches orcontacts the switch to operate the switch, the switch is changed to theshape that protrudes by sensing whether the user’s finger approaches orcontacts the switch. Further, by applying a structure in which thecarbon electrode layer that is attachable is provided, there is aneffect that proximity sensing can be realized through a simplestructure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objectives, features, and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a conceptual view illustrating an operation principle of ashape-transformable switch apparatus based on a MagnetorheologicalElastomer (MRE) according to an embodiment of the present invention;

FIG. 2 is a view illustrating a configuration of the shape-transformableswitch apparatus based on the MRE according to an embodiment of thepresent invention;

FIG. 3 is a view illustrating a configuration when a magnetic field isnot applied to the shape-transformable switch apparatus based on the MREaccording to an embodiment of the present invention;

FIG. 4 is a view illustrating a configuration when the magnetic field isapplied to the shape-transformable switch apparatus based on the MREaccording to an embodiment of the present invention; and

FIG. 5 is a view illustrating a sensing member of theshape-transformable switch apparatus based on the MRE according to anembodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Hereinafter, an exemplary embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.

Advantages and features of the present invention, and methods ofachieving the advantages and the features, will be apparent from theaccompanying drawings and from embodiments that are described in detailbelow.

However, the present invention is not limited to the embodimentsdisclosed below, but may be implemented in various different forms. Thepresent embodiments are intended to complete the invention of thepresent invention and provided to fully inform the skilled in the art towhich the invention pertains of the scope of the present invention. Thepresent invention is defined only by the scope of the claims.

Furthermore, detailed descriptions related to well-known functions orconfigurations may be omitted in order not to unnecessarily obscuresubject matter of the present invention.

FIG. 1 is a conceptual view illustrating an operation principle of ashape-transformable switch apparatus based on a MagnetorheologicalElastomer (MRE) according to an embodiment of the present invention, andFIG. 2 is a view illustrating a configuration of the shape-transformableswitch apparatus based on the MRE according to an embodiment of thepresent invention.

In addition, FIG. 3 is a view illustrating a configuration when amagnetic field is not applied to the shape-transformable switchapparatus based on the MRE according to an embodiment of the presentinvention, FIG. 4 is a view illustrating a configuration when themagnetic field is applied to the shape-transformable switch apparatusbased on the MRE according to an embodiment of the present invention,and FIG. 5 is a view illustrating a sensing member of theshape-transformable switch apparatus based on the MRE according to anembodiment of the present invention.

As illustrated in FIG. 2 , a shape-transformable switch apparatus basedon a Magnetorheological Elastomer (MRE) according to an embodiment ofthe present invention includes an electromagnet 100, a movement guide200, a Magnetorheological Elastomer (MRE) 300, and a switch cover 400.

First, the electromagnet 100 is provided inside a housing 10, a solenoidcoil 110 is wound on an outer circumferential surface of theelectromagnet 100, and a magnetic field is formed by a power applied tothe solenoid coil 110.

Preferably, the electromagnet 100 is formed of an Electro-permanentMagnet (EPM) in which an N-S polarity is changed by the power applied tothe solenoid coil 110. Here, the electromagnet 100 is a permanent magnethaving an N-S polarity, and it can be understood that the electromagnet100 has characteristics in which the N-S polarity thereof is changed bythe applied power.

In addition, the N-S polarity of the electromagnet 100 is changed by theapplied power. Further, when the power applied to the solenoid coil 110is turned off, a magnetic force of the solenoid coil 111 disappears, anda magnetic force of the electromagnet 100 at this time may be maintainedfor a predetermined period of time.

That is, even if the magnetic force of the solenoid coil 110 disappearssince the applied power is turned off, the electromagnet 100 configuredof the EPM may be maintained in a previous state for the predeterminedperiod of time, i.e., the magnetic force of the electromagnet 100 may bemaintained as before for the predetermined period of time.

The movement guide 200 is connected to the electromagnet 100 from insidethe housing 10. As illustrated in FIG. 4 , the movement guide 200 isconfigured to guide the electromagnet 100 to be moved in a movement pathof the electromagnet 100, the electromagnet 100 being moved upward alonga magnetic direction by the magnetic field generated as the power isapplied.

Specifically, the movement guide 200 is a non-magnetic material, andprovided as a pair of the movement guides 200 and is disposed uprightinside the housing 10. Further, the pair of the movement guides 200 isrespectively coupled to guide members 120 that are respectively providedat opposite end portions of the electromagnet 100, i.e., the pair of themovement guides 200 is respectively coupled to bushings as an example,and is configured to guide the movement path of the electromagnet 100that is optionally moved upward along the magnetic field direction.

The MRE 300 is disposed on an upper portion of the electromagnet 100.Further, the MRE 300 is configured to be changed from an initial softstate to a relatively hard state when the power is applied to thesolenoid coil 110 through a power supply portion 500 to generate themagnetic field.

In other words, as illustrated in FIG. 1 , when the MRE 300 is in astate in which the magnetic field is not applied, the MRE 300 maintainsthe initial soft state in which iron particles \320 inside an elastomer310 are not arranged. Then, when the power is applied to the solenoidcoil 110, the iron particles 320 are arranged inside the elastomer 310,and the MRE 300 is changed from the initial soft state to the relativelyhard state.

More preferably, the MRE 300 is a MRE having a structure in which a sizethereof in the initial soft state becomes small and a state thereofbecomes the hard state when the magnetic field is applied. Further,conventionally, the MRE 300 is formed in a flat plate shape.

Therefore, when the MRE 300 becomes the relatively hard state due to theapplied magnetic field that is generated on the electromagnet 100, theMRE 300 may provide a kinesthetic sensation to a user who contacts theMRE 300.

A strength in which the MRE 300 is compressed is changed according to anintensity of the applied magnetic field that is formed on theelectromagnet 100, so that an intensity of the kinesthetic sensation maybe adjusted. Further, the larger the intensity of the applied magneticfield is, the harder state of the MRE 300 may be formed.

The switch cover 400 is disposed on an upper portion of the housing 10,and is provided such that the switch cover 400 forms a switch shape andprotrudes outward as the MRE 300 is moved upward.

That is, the switch cover 400 is disposed to be in a flat shape suchthat the switch cover 400 is in contact with an upper plate 12 whichforms the upper portion of the housing 10. Further, the switch cover 400may be formed of a plastic material having elasticity. Morespecifically, the switch cover 400 may be formed of thermoplasticpolyurethane (TPU).

Accordingly, in a state in which the MRE 300 is inserted into anddisposed in a mounting hole H that is provided in a center of the upperplate 12, the state of the MRE 300 becomes the relatively hard statesince the magnetic field is formed on the electromagnet 100 by the powerapplied to the solenoid coil 110. At this time, when the electromagnet100 is moved upward in the magnetic field direction along the movementguide 200, the MRE 300 is pressed and pushed upward, so that an area ofthe switch cover 400 facing the mounting hole H protrudes outward.

In this manner, by material characteristics of the switch cover 400,when the center of the switch cover 400 protrudes outward by the MRE 300that is pushed upward, the user may push the switch cover 400 thatprotrudes upward while the MRE 300 is in the relatively hard state whenthe user operates a switch, so that there is an effect that an operationsensation may be provided to the user. Therefore, the kinestheticsensation of a hard feeling according to the operation of the switch maybe provided the user.

Here, when the user presses the center of the switch cover 400 thatprotrudes, the power applied to the solenoid coil 110 is turned off.Therefore, since the magnetic field is not formed on the electromagnet100, the MRE 300 becomes the initial state.

More specifically, when the power applied to the solenoid coil 110 bythe power supply portion 500 is turned off and then the magnetic fieldis not formed on the electromagnet 100, the N-S polarity is changed.That is, the polarity of the electromagnet 100 as illustrated in FIG. 4is changed to the polarity of the electromagnet 100 as illustrated inFIG. 3 .

As a result, when the polarity is changed according to the release ofthe magnetic field, the MRE 300 returns to the initial shape thereof andis moved downward at the same time by gravity and elasticity that theMRE 300 has. Accordingly, the electromagnet 100 is also moved downwardalong the movement guide 200 and returns to an initial position thereof.Finally, the switch shape, which protrudes on the center of the switchcover 400, becomes an initial shape, i.e., the switch shape becomes theflat shape that is the same as the upper plate 12, so that the switchshape disappears.

Therefore, by using the electromagnet 100 and the MRE 300 optionally,the center of the switch cover 400 protrudes outward when the operationof the user is performed, and the center of the switch cover 400 isreleased from protruding in other states. Therefore, the kinestheticsensation of hard feeling may be optionally provided according to theoperation of the switch, and also a neat exterior appearance may beformed.

Meanwhile, as illustrated in FIG. 5 , the shape-transformable switchapparatus based on the MRE according to an embodiment of the presentinvention may further include a sensing member 600.

The sensing member 600 is disposed inside the switch cover 400, and isconfigured to sense a contact state of a user’s finger or the like byusing a change in a capacitance that is changed according to an approachdistance of an object.

Preferably, the sensing member 600 is formed of a carbon electrode layerand is configured to realize a function of a capacitive proximity sensorhaving a simple structure. Further, the sensing member 600 includes alayer formed of a tape so that the sensing member 600 is attached to anddisposed at an inner side of the switch cover 400.

That is, a conventional touch screen panel is an input device whichallows a user to operate a display device by touching a display screenbutton of the display device with the user’s finger and which can beeasily operated by anyone. Further, as types of the touch screen panelfor an example, a resistive type, a capacitive type, an infrared type,an ultrasonic type, and so on are used, and the capacitive type ismainly applied.

Such a capacitive type is a type using a capacitance in a human body,and has a principle in which the capacitance in the human body is usedwhen the user touches the touch screen panel and which detects andcalculate a size of an area where the amount of the current is changedand then detects a position. Further, by using this characteristics, thesensing member 600 is configured to sense the contact state of theuser’s finger or the like through the change in capacitance that ischanged according to an approach distance of the user’s finger.

As described above, by using the sensing member 600, when the change incapacitance is increased, the power is optionally applied to theelectromagnet 100 by an operation control of the power supply portion500, and the MRE 300 is changed to the relatively hard state by changingthe N-S polarity since the magnetic field is formed, so that the shapeof the center of the switch cover 400 may be changed to the shape thatprotrudes (see FIG. 4 ).

In other words, if the user approaches the switch so as operate theswitch, the change in capacitance that is detected according to acurrent flow change caused by the approach distance between the user’sfinger and the sensing member 600 is also changed. Therefore, by usingthis situation, when the change in capacitance is detected by thesensing member 600, the power is applied to the electromagnet 100through the power supply portion 500, so that the electromagnet 100 ismoved upward in the magnetic field direction along the movement guide200. Finally, the MRE 300 is pushed upward, and the center of the switchcover 400 facing the mounting hole H protrudes outward.

As such, in a state in which the shape of the center of the switch cover400 protrudes, when it is determined that the user’s finger contacts theswitch cover 400 and a pressure is applied to the switch cover 400, avoltage applied to the electromagnet 100 is turned off. Therefore, whenthe pressure by the user is applied to the center of the switch cover400 that protrudes, the switch cover 400 returns to the flat shape,i.e., the initial shape, so that the user may recognize that the switchis effectively operated.

The present invention uses the electromagnet that forms the magneticfield by the power applied to the solenoid coil, and uses the MRE havingcharacteristics in which the MRE maintains the initial soft state whenthe magnetic field is not applied but the MRE is changed to therelatively hard state when the magnetic field is applied. By using theelectromagnet and the MRE, when the magnetic field is formed, theelectromagnet is moved along the movement guide, and the MRE that ischanged to the hard state is moved upward, so that the switch having theshape that protrudes is formed. Therefore, there is an effect that thekinesthetic sensation of the hard feeling according to the operation ofthe switch may be provided according to whether or not the magneticfield is applied.

In addition, in the present invention, when the user’s finger approachesor contacts the switch to operate the switch, the switch is changed tothe shape that protrudes by sensing whether the user’s finger approachesor contacts the switch. Further, by applying a structure in which thecarbon electrode layer that is attachable is provided, there is aneffect that proximity sensing can be realized through a simplestructure.

While the present invention has been and described with reference toembodiment(s) illustrated in the drawings, the embodiment(s) are onlyillustrative, and it will be understood that various modifications canbe made by those skilled in the art, and all or some of the describedembodiment(s) may be optionally configured in combination. Accordingly,the true technical scope of the present invention should be defined bythe technical spirit of the appended claims.

What is claimed is:
 1. A shape-transformable switch apparatuscomprising: an electromagnet arranged inside a housing, wherein theelectromagnet has an outer circumferential surface wound with a solenoidcoil and is configured to provide a magnetic field when a power isapplied to the solenoid coil; a Magnetorheological Elastomer (MRE)disposed on an upper portion of the electromagnet, wherein the MRE isconfigured to: change from an initial soft state to a relatively hardstate when the power is applied to the solenoid coil, and be pressed andmove upward when the electromagnet moves upward; and a switch coverdisposed on an upper portion of the housing, the switch cover configuredto form a switch shape thereby protruding outward when the MRE moves inan upward direction.
 2. The apparatus of claim 1, further comprising amovement guide connected to the electromagnet inside the housing,wherein the movement guide is configured to provide a movement path forthe electromagnet so that the electromagnet is able to move in theupward direction or a downward direction.
 3. The apparatus of claim 2,wherein the movement guide comprises a pair of upright movement guidesinside the housing, and wherein the pair of movement guides is coupledto guide members arranged at opposite end portions of the electromagnetrespectively.
 4. The apparatus of claim 2, further comprising a powersupply, wherein the power supply is configured to turn off the power tothe solenoid coil when an external pressure is applied to the MRE whilethe switch cover is in the switch shape thereby allowing the MRE to movein the downward direction along the movement guide.
 5. The apparatus ofclaim 4, wherein the switch cover is configured to change from theswitch shape to an initial shape when the MRE is changed to the initialstate.
 6. The apparatus of claim 1, further comprising a power supplyconfigured to supply the power to the solenoid coil.
 7. The apparatus ofclaim 1, wherein the electromagnet is an electro-permanent magnet (EPM)which is configured to change N-S polarity based on the power applied tothe solenoid coil.
 8. The apparatus of claim 1, wherein the upperportion of the housing comprising a mounting hole in a center, andwherein the MRE is arranged in and coupled to the mounting hole.
 9. Theapparatus of claim 8, wherein the MRE is configured to protrude from themounting hole when the MRE is pressed by the electromagnet and when theMRE changes to the relatively hard state by the electromagnet.
 10. Theapparatus of claim 9, wherein the switch cover comprises an elasticmaterial, and wherein the switch cover is configured to change its shapefrom an initial state to a protruding state when the MRE protrudesoutward through the mounting hole.
 11. The apparatus of claim 1, furthercomprising a sensor disposed inside the switch cover, the sensorconfigured to sense a distance of an approaching object.
 12. Theapparatus of claim 11, wherein the sensor is configured to measure acapacitance based on the distance of the approaching object.
 13. Theapparatus of claim 12, wherein the sensor comprises a carbon electrodelayer attached to an inner side of the switch cover.
 14. The apparatusof claim 13, wherein the carbon electrode layer is directly attached tothe inner side of the switch cover.
 15. The apparatus of claim 14,wherein the switch cover comprises an elastic plastic material.
 16. Theapparatus of claim 11, wherein a power supply is configured to providethe power to the electromagnet when the sensor detects the approachingobject thereby allowing the MRE to move in the upward direction.
 17. Theapparatus of claim 16, wherein the sensor is configured to detect theapproaching object by a change in capacitance.